Most clinical disorders do not arise due to a single biological change, but rather are the result of an interaction of multiple factors. Thus, different individuals affected by the same clinical condition may present with a different range of symptoms or a different extent of symptoms, depending on the specific changes within each individual. The ability to determine disease status on an individual basis thus would be useful for accurate assessment of a subject's specific status. There is a need, however, for reliable methods for diagnosing or determining predisposition to clinical conditions, or for assessing a subject's disease status or response to treatment.